The present invention relates to a recording method and an optical disc apparatus. In particular, the present invention is suitably applied to an optical disc apparatus corresponding to a multilayered optical disc having a plurality of recording layers provided therein.
Conventionally, in the optical disc apparatus, an adjustment process of the recording power (recording power adjustment process) called OPC (Optimum Power Calibration) has been carried out in recording data on an optical disc. In the OPC, a test writing of predetermined data is carried out to a test writing area provided in the innermost periphery or the outermost periphery of an optical disc, and then the most suitable recording power (hereinafter, referred to as the optimum recording power) is detected based on a reproduced waveform of this test written data.
However, since such OPC is carried out prior to starting the data recording, it cannot respond to a change in the optimum recording power associated with the environmental change after starting the recording or a change of the recording position on an optical disc. Then, as a recording power control method corresponding to such a change in the optimum recording power, a method called Walking OPC has been proposed in recent years.
The Walking OPC is a method, in which at certain intervals or at regular time intervals, the recording is interrupted to reproduce a recording trailer and evaluate the data recording quality in this recording trailer and then the recording power is corrected based on this evaluation result. The recording power control based on such Walking OPC has been widely used in recent years because it can secure a high recording quality to ensure reproduction compatibility.
In such Walking OPC, a parameter called a β value indicative of the asymmetry of amplitude is used as an index of the recording quality. Then, in the Walking OPC, a correction factor for the recording power is calculated based on a predetermined β value to be targeted (hereinafter, suitably referred to as a target β value) and a β value obtained by reproducing the recording trailer at certain intervals or at regular time intervals (hereinafter, suitably referred to as a measured β value), and then based on this correction factor the recording power is corrected.
The techniques on the OPC are disclosed in JP Patent No. 3720624, WO 2005/031718, JP-A-2007-164954, and JP-A-2005-259257.